A magnetic resonant wireless power transfer system with high-order LC compensation at the receiver

Abstract

This invention provides a magnetic resonance wireless power transfer system with high-order LC compensation at the receiving end, relating to the field of wireless power transfer technology. It includes a transmitter and a receiver. The transmitter includes a transmitter compensation network and a transmitting coil. The transmitter compensation network is connected to the transmitting coil. An AC signal is input to the transmitter compensation network, which makes the current in the transmitting coil exhibit constant current characteristics. The transmitting coil transmits electrical energy to the receiving coil through magnetic coupling. The receiver includes a receiving coil and a receiver compensation network. The receiver compensation network includes a high-order LC structure with several orders of LC. The receiving coil is connected to the receiver compensation network and receives the electrical energy emitted by the transmitting coil. The receiver compensation network stabilizes the transmission efficiency. When the load changes, the LCC-C(LC) structure... n Higher-order topologies have higher efficiency and stability compared to traditional topologies.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission technology, and more specifically, to a magnetic resonant wireless power transmission system with high-order LC compensation at the receiver. Background Technology

[0002] Wireless power transmission technology offers advantages over wired power transmission, including stability, safety, avoidance of port aging and wear, reduced risk of arcing and leakage, and less susceptibility to harsh environments such as humidity and dust. Typically, in wireless power transmission systems, to achieve resonance between the transmitting and receiving coils and improve system power transmission power and efficiency, compensation networks are added to the transmitting and receiving circuits to compensate for both coils simultaneously. The compensation network plays a crucial role in magnetically resonant coupled wireless power transmission systems. Configuring the parameters of the bilateral compensation network of the transceiver mechanism can alter the system's equivalent impedance characteristics, thereby minimizing reactive power and improving the overall power factor and coupling between the transmitting and receiving coils. However, the transmission efficiency of current LCC-S and LCC-CCL composite resonant compensation network topologies still has room for improvement.

[0003] The existing LCC-S type wireless power transfer system and parameter design method have relatively low system transmission efficiency and poor system transmission stability under light load conditions. As the load increases, the system transmission efficiency drops rapidly. When using wireless power transfer to charge the battery, it is not suitable for variable load charging modes during the battery charging process. Summary of the Invention

[0004] To overcome the above-mentioned technical problems, this invention provides a magnetic resonant wireless power transmission system with higher-order LC compensation at the receiver, which offers higher system transmission efficiency and stability.

[0005] The technical solution of this invention is as follows:

[0006] A magnetic resonant wireless power transfer system with high-order LC compensation at the receiver includes: a transmitter and a receiver;

[0007] The transmitter includes a transmitter compensation network and a transmitter coil. The transmitter compensation network is connected to the transmitter coil. An AC signal is input to the transmitter compensation network. The transmitter compensation network makes the current in the transmitter coil exhibit constant current characteristics. The transmitter coil transmits electrical energy to the receiver coil through magnetic coupling.

[0008] The receiving end includes a receiving coil and a receiving end compensation network. The receiving end compensation network includes a high-order LC structure with several orders of LC. The receiving coil is connected to the receiving end compensation network and receives the electrical energy emitted by the transmitting coil. The receiving end compensation network stabilizes the transmission efficiency.

[0009] This technical solution proposes a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end, including a transmitter and a receiver. The transmitter is an LCC series-parallel resonant structure, and the receiver is equipped with a high-order LC structure. The transmitting coil current is only related to the input voltage and the parameters in the transmitter compensation network, and is independent of the load. When the load changes under ideal conditions, the transmitting coil current remains unchanged, and the constant current of the transmitting coil allows the system to maintain stable transmission characteristics. In the receiver end, when the number of LCs in the high-order LC structure is odd, the receiver output exhibits constant current characteristics; when the number of LCs is even, the receiver output exhibits constant voltage characteristics. Therefore, when the load changes, the magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end has higher efficiency stability compared to traditional LCC-S and LCC-CCL topologies, and its efficiency under light loads is significantly higher than that of traditional topologies.

[0010] Furthermore, the transmitter compensation network is an LCC series-parallel resonant network, which includes a capacitor C connected in series with the transmitter coil. T The capacitor C connected in parallel with the transmitting coil P and the inductor L connected in parallel with the transmitting coil P The transmitter also includes an inverter circuit. The input of the inverter circuit is connected to a DC power supply, and the output of the inverter circuit is connected to the transmitter compensation network. The inverter circuit converts the DC input into an AC signal output.

[0011] Furthermore, the inverter circuit is a full-bridge inverter circuit, which includes MOSFETs Q1, Q2, Q3, and Q4. The drains of MOSFETs Q1 and Q3 are connected, the sources of MOSFETs Q2 and Q4 are connected, the source of MOSFET Q1 is connected to the drain of MOSFET Q2, and the source of MOSFET Q3 is connected to the drain of MOSFET Q4. The drains of MOSFETs Q3 and Q2 serve as the input terminals of the inverter circuit, and the sources of MOSFETs Q1 and Q4 serve as the output terminals of the inverter circuit. MOSFETs Q1, Q2, Q3, and Q4 are all N-type MOSFETs, and the gates of MOSFETs Q1, Q2, Q3, and Q4 are all connected to a PWM signal.

[0012] Furthermore, the receiving end also includes a rectifier circuit, the input of which is connected to the output of a higher-order LC structure, and the output of which is connected to a load.

[0013] Furthermore, the rectifier circuit is a full-bridge rectifier circuit, and the rectifier circuit includes diode D. R1 diode D R2 diode D R3 and diode DR4 Diode D R1 The negative terminal of the diode D is connected. R2 The negative terminal of diode D R3 The positive terminal of the diode D is connected. R4 The positive terminal of diode D R1 The positive terminal of the diode D is connected. R3 The negative terminal of diode D R2 The positive terminal of the diode D is connected. R4 The negative terminal of diode D; R1 The positive electrode and diode D R4 The negative terminal of diode D serves as the input terminal of the rectifier circuit. R3 The positive electrode and diode D R2 The negative terminal is used as the output terminal of the rectifier circuit.

[0014] Furthermore, the rectifier circuit also includes a rectifier capacitor C. o rectifier capacitor C o The two ends are connected to the two output terminals of the rectifier circuit, respectively.

[0015] In the above technical solution, through the rectifier capacitor C o The high-frequency waveform output from the diode is converted into direct current and supplied to the load device.

[0016] Furthermore, the rectifier capacitor C o The capacitor is a polarized capacitor, and the rectifier capacitor C is... o The positive terminal of the diode D is connected. R2 The negative terminal, rectifier capacitor C o The negative terminal of the diode D is connected. R3 The positive pole.

[0017] Furthermore, the higher-order LC structure in the receiver compensation network includes LC structures of orders two to ten. Each order LC structure includes a capacitor and an inductor. The capacitor has a first connection terminal and a second connection terminal, and the inductor has a first connection terminal and a second connection terminal. The second connection terminal of the capacitor in each order LC structure is connected to the first connection terminal of the inductor. The connection relationship between two adjacent order LC structures is as follows: the second connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the inductor in the previous order LC, and the first connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the capacitor in the previous order LC. The first connection terminal and the second connection terminal of the capacitor in the first order LC structure in the higher-order LC structure serve as the input terminal of the higher-order LC structure, and the first connection terminal of the capacitor and the second connection terminal of the inductor in the last order LC structure in the higher-order LC structure serve as the output terminal of the higher-order LC structure.

[0018] Furthermore, the sum of the reactances of each mesh in the system is zero, and the system operates in a resonant state. According to the KVL equations, the receiver circuit in the resonant state has the following relationship:

[0019]

[0020] Among them, U IN I is the input voltage at the transmitter. T Z is the current in the transmitting coil. CP For the capacitor C in the transmitter compensation network P Capacitive reactance, I IN For the input current at the transmitter, I R To receive the coil current, R L For the load of the receiving end, I O I is the output current of the receiving end. n-1 Z represents the current in the (n-1)th order LC structure. M For mutual inductance, C n For a capacitor of the nth order LC structure, L n For an inductor of the nth order LC structure, Z Cn C n The capacitance, Z Ln For L n The inductive reactance, ω is the resonant angular frequency of the circuit;

[0021] Input current I at the transmitter IN The expression is:

[0022]

[0023] transmitting coil current I T The expression is:

[0024]

[0025] From the current I in the transmitting coil T From the expression, we can see that the transmitting coil current I T Only related to the input voltage and the capacitor C in the transmitter compensation network P It is related to the load, but not to the load; the constant current of the transmitting coil keeps the system's transmission characteristics stable.

[0026] Receiver coil current I R The expression is:

[0027]

[0028] The output current I of the receiver O The expression is:

[0029]

[0030] From the output current I OAs can be seen from the expression, when the order n of the higher-order LC structure is odd, the topological output current of this circuit topology family is independent of the load and exhibits constant current characteristics; when the order n of the higher-order LC structure is even, the output voltage at the receiving end of this circuit topology family is independent of the load and exhibits constant voltage characteristics.

[0031] Furthermore, the higher-order LC structure in the receiver compensation network is a second-order LC structure, and the transmitter also includes an inductor L connected in series with the input power supply. P The transmitter and receiver have a total of five meshes. Write the KVL equations for the five voltage meshes:

[0032]

[0033]

[0034] U IN =R1I IN -Z CP CI O =R1DI O -Z CP CI O =(R1D-Z) CP C)I O =EI O

[0035]

[0036] Solving for the efficiency expression of the magnetic resonant wireless power transfer system, where the higher-order LC structure in the receiver compensation network is a second-order LC structure, yields:

[0037]

[0038] Among them, Z M For mutual inductance, U IN I is the input voltage at the transmitter. T Z is the current in the transmitting coil. CP For the capacitor C in the transmitter compensation network P The capacitance, Z LP For inductor L P resistance, I IN For the input current at the transmitter, I R To receive the coil current, Z Cn Z is the capacitive reactance of the nth-order LC structure. Ln For L n resistance, R L For the load of the receiving end, I O I is the output current of the receiving end. n-1R1 represents the current in the (n-1)th order LC structure, and R2, R3, R4, and R5 are all equivalent line resistances.

[0039] This invention proposes a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end, comprising a transmitter and a receiver end. The transmitter end is an LCC series-parallel resonant structure, and the receiver end is equipped with a high-order LC structure. Compared with the prior art, the beneficial effects of this invention are: the transmitting coil current is only related to the input voltage and the parameters in the transmitter end compensation network, and is independent of the load. When the load changes under ideal conditions, the transmitting coil current will not change, and the constant current of the transmitting coil can maintain the system's stable transmission characteristics. In the receiver end, when the number of LCs in the high-order LC structure is odd, the output of the receiver end exhibits constant current characteristics; when the number of LCs in the high-order LC structure is even, the output of the receiver end exhibits constant voltage characteristics. Therefore, when the load changes, the magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end has higher efficiency stability than the traditional LCC-S and LCC-CCL topologies, and its efficiency under light load is much higher than that of the traditional topologies. Attached Figure Description

[0040] Figure 1 A schematic diagram of a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver;

[0041] Figure 2 A schematic diagram of the traditional LCC-S and LCC-CCL composite resonant compensation network topology;

[0042] Figure 3 A schematic diagram of a family of circuit topologies for a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver.

[0043] Figure 4 A schematic diagram of the equivalent circuit model of a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver.

[0044] Figure 5 A schematic diagram of the equivalent circuit model of a magnetic resonant wireless power transfer system with a second-order LC structure;

[0045] Figure 6 The above are simulation curves showing the transmission efficiency of the present invention and the traditional LCC-S structure as a function of load.

[0046] Figure 7 The figure shows the experimental curves of transmission efficiency of the present invention and the traditional LCC-S structure as a function of load. Detailed Implementation

[0047] To clearly illustrate the magnetic resonance wireless power transmission system with high-order LC compensation at the receiver of the present invention, the present invention will be further described in conjunction with embodiments and accompanying drawings, but this should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] A magnetic resonant wireless power transfer system with high-order LC compensation at the receiver, such as Figure 1 As shown, it includes: a transmitter and a receiver;

[0050] The transmitter includes a transmitter compensation network and a transmitter coil L. T The transmitter compensation network is connected to the transmitter coil L. T The AC signal is input to the transmitter compensation network, which converts the input electrical energy into high-frequency voltage and current signals. These high-frequency voltage and current signals are then input to the transmitting coil L. T transmitting coil L T The system generates electrical energy, and through a compensation network at the transmitting end, the current in the transmitting coil exhibits constant current characteristics. The transmitting coil then transmits the electrical energy to the receiving coil via magnetic coupling.

[0051] The receiving end includes a receiving coil L R The receiver compensation network includes a high-order LC structure with several orders of LC; the receiver coil L R Connect the receiving end compensation network, receiving coil L R Receiver / transmitter coil L T The generated electrical energy is used to compensate for network stability and transmission efficiency at the receiving end.

[0052] This embodiment proposes a magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end, including a transmitter and a receiver. The transmitter is an LCC series-parallel resonant structure, and the receiver is equipped with a high-order LC structure. The transmitting coil current is only related to the input voltage and the parameters in the transmitter compensation network, and is independent of the load. When the load changes under ideal conditions, the transmitting coil current remains unchanged, and the constant current of the transmitting coil allows the system to maintain stable transmission characteristics. In the receiver end, when the number of LCs in the high-order LC structure is odd, the receiver output exhibits constant current characteristics; when the number of LCs in the high-order LC structure is even, the receiver output exhibits constant voltage characteristics. Therefore, when the load changes, the magnetic resonant wireless power transfer system with high-order LC compensation at the receiver end has higher efficiency stability compared to traditional LCC-S and LCC-CCL topologies, and its efficiency under light loads is significantly higher than that of traditional topologies.

[0053] Example 2

[0054] Based on Example 1, such as Figure 1As shown, the transmitter compensation network in this embodiment is an LCC series-parallel resonant network. The transmitter also includes an inverter circuit. The input terminal of the inverter circuit is connected to a DC power supply, and the output terminal of the inverter circuit is connected to the transmitter compensation network. The inverter circuit converts the DC input into an AC signal output. The inverter circuit is a full-bridge inverter circuit, which includes MOSFETs Q1, Q2, Q3, and Q4. The drains of MOSFETs Q1 and Q3 are connected, the sources of MOSFETs Q2 and Q4 are connected, the source of MOSFET Q1 is connected to the drain of MOSFET Q2, and the source of MOSFET Q3 is connected to the drain of MOSFET Q4. The drains of MOSFETs Q3 and Q2 serve as the input terminals of the inverter circuit, and the sources of MOSFETs Q1 and Q4 serve as the output terminals of the inverter circuit. MOSFETs Q1, Q2, Q3, and Q4 are all N-type MOSFETs, and their gates are all connected to a PWM signal. The model number of MOSFETs Q1, Q2, Q3, and Q4 is FQPF12N60.

[0055] The receiving end described in this embodiment further includes a rectifier circuit. The input terminal of the rectifier circuit is connected to the output terminal of a high-order LC structure, and the output terminal of the rectifier circuit is connected to a load. The rectifier circuit is a full-bridge rectifier circuit and includes a diode D. R1 diode D R2 diode D R3 and diode D R4 Diode D R1 The negative terminal of the diode D is connected. R2 The negative terminal of diode D R3 The positive terminal of the diode D is connected. R4 The positive terminal of diode D R1 The positive terminal of the diode D is connected. R3 The negative terminal of diode D R2 The positive terminal of the diode D is connected. R4 The negative terminal of diode D; R1 The positive electrode and diode D R4 The negative terminal of diode D serves as the input terminal of the rectifier circuit. R3 The positive electrode and diode D R2 The negative terminal serves as the output terminal of the rectifier circuit. The rectifier circuit also includes a rectifier capacitor C. o rectifier capacitor C o The two ends are respectively connected to the two output terminals of the rectifier circuit. The rectifier capacitor C o The capacitor is a polarized capacitor, and the rectifier capacitor C is... o The positive terminal of the diode D is connected. R2 The negative terminal, rectifier capacitor C oThe negative terminal of the diode D is connected. R3 The positive pole.

[0056] In this embodiment, the high-order LC structure in the receiver compensation network includes LC structures of orders two to ten. Each order LC structure includes a capacitor and an inductor. The capacitor has a first connection terminal and a second connection terminal, and the inductor has a first connection terminal and a second connection terminal. The second connection terminal of the capacitor in each order LC structure is connected to the first connection terminal of the inductor. The connection relationship between two adjacent order LC structures is as follows: the second connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the inductor in the previous order LC, and the first connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the capacitor in the previous order LC. The first connection terminal and the second connection terminal of the capacitor in the first order LC structure in the high-order LC structure serve as the input terminal of the high-order LC structure, and the first connection terminal of the capacitor and the second connection terminal of the inductor in the last order LC structure in the high-order LC structure serve as the output terminal of the high-order LC structure.

[0057] Example 3

[0058] In wireless power transmission systems, to achieve resonance between the inductance of the receiving and transmitting coils and improve the system's power transmission efficiency, compensation networks are added to the transceiver mechanism to simultaneously compensate the transmitting and receiving coils. The compensation network plays a crucial role in magnetic resonant coupling wireless charging systems. Configuring the parameters of the bilateral compensation network of the transceiver mechanism can change the system's equivalent impedance characteristics, thereby minimizing the system's reactive power and improving the overall power factor and coupling between the transmitting and receiving coils. Depending on the series-parallel combination of the bilateral compensation networks, there are four basic topologies: SS, SP, PP, and PS. Due to the limitations of the basic topologies, composite resonant topologies have been introduced, including LCL-S, LCC-S, LCL-LCL, and LCC-LCC topologies.

[0059] Existing compensation networks similar to this invention are LCC-S type and LCC-CCL type composite resonant topologies. Schematic diagrams of the LCC-S and LCC-CCL composite resonant compensation network topologies are shown below. Figure 2 As shown, the LCC-S and LCC-CCL composite resonant compensation networks have the following drawbacks:

[0060] 1. Under light load conditions, the system transmission efficiency is relatively low.

[0061] 2. The system's transmission efficiency is unstable. As the load increases, the system's transmission efficiency drops rapidly, making it unsuitable for variable load charging modes during battery charging.

[0062] This embodiment proposes a family of circuit topologies for a high-order LC-compensated magnetic resonant wireless power transfer system at the receiver. The circuit structure of the family of topologies is as follows: Figure 3 As shown, the circuit topology family includes a transmitter compensation network and a transmitter coil at the transmitter end, and a receiver coil and a receiver compensation network at the receiver end. The transmitter compensation network is an LCC series-parallel resonant network, and the receiver compensation network is a C(LC) network. n The resonant network has different topologies depending on the value of n chosen; therefore, the family of circuit topologies for the receiver-side high-order LC-compensated magnetic resonant wireless power transfer system in this embodiment can be referred to as LCC-C(LC). n Higher-order topologies.

[0063] The receiver compensation network includes a high-order LC structure with several orders of LC and a receiver compensation capacitor C. R Receiver compensation capacitor C R Connect the input terminal of the higher-order LC structure;

[0064] A high-order LC structure includes n-order LC structures. Each order LC structure includes a capacitor and an inductor. The capacitor has a first connection terminal and a second connection terminal, and the inductor has a first connection terminal and a second connection terminal. The second connection terminal of the capacitor in each order LC structure is connected to the first connection terminal of the inductor. The connection relationship between adjacent order LC structures is as follows: the second connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the inductor in the previous order LC, and the first connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the capacitor in the previous order LC. The first and second connection terminals of the capacitor in the first order LC structure in the high-order LC structure serve as the input terminals of the high-order LC structure, and the first and second connection terminals of the capacitor and inductor in the last order LC structure in the high-order LC structure serve as the output terminals of the high-order LC structure. The receiving end compensation capacitor C... R Connect the second terminal of the capacitor.

[0065] In the entire magnetic resonant wireless power transfer system, the resonant network plays a crucial role in the power transmission process. For the LCC series-parallel resonant network at the transmitting end, its main function is to convert the input electrical energy into the required high-frequency voltage and current signals, which are then applied to the transmitting coil for efficient power transmission. By rationally designing the inductance and capacitance parameters of the LCC series-parallel resonant network, its reliability and adaptability can be improved. On the other hand, for the receiving end, by rationally designing the inductance value and size of the receiving coil, and appropriately selecting the C(LC) value at the receiving end... n The parameters of the resonant network can improve the stability of the system's transmission efficiency and ensure the stability of the transmission efficiency when the load changes.

[0066] Figure 3The input AC signal is output through the inverter circuit, such as... Figure 1 As shown, the input terminal of the inverter circuit is connected to a DC power supply, and the output terminal of the inverter circuit is connected to a transmitter compensation network. The inverter circuit converts the DC input into an AC signal output. The inverter circuit is a full-bridge inverter circuit, which includes MOSFETs Q1, Q2, Q3, and Q4. The drains of MOSFETs Q1 and Q3 are connected, the sources of MOSFETs Q2 and Q4 are connected, the source of MOSFET Q1 is connected to the drain of MOSFET Q2, and the source of MOSFET Q3 is connected to the drain of MOSFET Q4. The drains of MOSFETs Q3 and Q2 serve as the input terminals of the inverter circuit, and the sources of MOSFETs Q1 and Q4 serve as the output terminals of the inverter circuit.

[0067] The characteristics of the transmitter and receiver resonant network circuits in a family of receiver-end high-order LC-compensated magnetic resonant wireless power transfer system circuit topologies in this embodiment are analyzed, which can... Figure 3 The circuit is equivalent to obtain, as follows Figure 4 The equivalent circuit model of a high-order LC-compensated magnetic resonant wireless power transfer system at the receiver.

[0068] Z M The mutual inductance between the receiving coil and the transmitting coil is given by the formula, where ω is the resonant angular frequency of the circuit, and Z is the mutual inductance between the receiving coil and the transmitting coil. M The expressions for other impedances are as follows:

[0069]

[0070] According to the KVL equations, the receiving circuit in the resonant state has the following relationship:

[0071]

[0072] When setting the inductance and capacitance parameters of the compensation network, it is necessary to ensure that the sum of the reactance of each mesh is zero so that the system operates in a resonant state.

[0073]

[0074]

[0075]

[0076]

[0077] From the current I in the transmitting coil TAs can be seen from the expression, regardless of the value of n in the topology family, all transmission coils in this family have the same expression, which depends only on the input voltage and the parameters in the compensation network, and is independent of the load. This means that the topology of this family has the same characteristic: when the load changes under ideal conditions, the current in the transmission coil does not change. The constant current of the transmitting coil in this family of topologies allows the system to maintain stable transmission characteristics.

[0078] The output current I of the receiving end O As can be seen from the expression, when n is odd, the expression for the output current depends on the mutual inductance, compensation network parameters, and input voltage. In this case, the topology output current of this topology family is independent of the load and exhibits a constant current characteristic. When n is even, the expression for the output current depends on the mutual inductance, compensation network parameters, input voltage, and load, and the output current is positively correlated with the input voltage and negatively correlated with the load. This means that when n is even, the topology output voltage of this topology family is independent of the load and exhibits a constant voltage characteristic.

[0079] Considering this embodiment, a set of LCC-C(LC) n The complexity of higher-order topologies is discussed here, taking only the conventional LCC-S topology (n=0) and the LCC-C(LC) of a magnetic resonant wireless power transfer system with a second-order LC structure (n=2) as examples. 2 A theoretical comparative analysis of circuit topologies on system transmission efficiency is conducted, specifically LCC-C (LC). 2 The equivalent model of the circuit topology is as follows Figure 5 A schematic diagram of the equivalent circuit model of a magnetic resonant wireless power transfer system with a second-order LC structure is shown.

[0080] Write the KVL equations for the five voltage meshes:

[0081]

[0082]

[0083] U IN =R1I IN -Z CP CI O =R1DI O -Z CP CI O =(R1D-Z) CP C)I O =EI O

[0084]

[0085] Solving for LCC-C(LC) yields... 2 The efficiency expression for the circuit topology is:

[0086]

[0087] Similarly, by using the above method to solve for the traditional LCC-S topology for n=0, we can obtain:

[0088]

[0089] The relationship between efficiency and load curves was simulated using MATLAB, as follows: Figure 6 As shown, the analysis yields the following: (1) When the load changes, LCC-C(LC) 2 The transmission efficiency of this circuit topology is higher than that of the traditional LCC-S topology, exhibiting greater stability. (2) LCC-C (LC) 2 The efficiency of the circuit topology under light load is much higher than that of LCC-S.

[0090] pass Figure 7 The experimental curves of transmission efficiency versus load for the present invention and the traditional LCC-S structure show that, in the experiment of transmission efficiency versus load variation for the magnetic resonant wireless power transmission system with a second-order LC structure at the receiving end and the traditional LCC-S structure, when the load changes, the efficiency of LCC-C(LC) varies. n Higher-order topologies exhibit higher efficiency and stability compared to traditional topologies. LCC-C(LC) n Higher-order topologies are far more efficient than traditional topologies under light loads.

[0091] Example 4

[0092] Based on Embodiment 3, this embodiment further includes an inverter circuit at the transmitting end and a rectifier circuit at the receiving end, such as... Figure 1 As shown, the input terminal of the inverter circuit is connected to a DC power supply, and the output terminal is connected to a transmitter compensation network. The inverter circuit converts the DC input into an AC signal output. The rectifier circuit includes a power diode D. R1 diode D R2 diode D R3 diode D R4 Filter capacitor C O Load R Load The input terminal of the rectifier circuit is connected to the output terminal of the high-order LC structure, and the output terminal of the rectifier circuit is connected to the load. The function of the rectifier circuit is to convert the high-frequency AC sine wave received by the high-order LC structure resonant network at the receiving end into a diode D at the receiving end. R1 diode D R2 diode D R3 diode D R4 It is transformed into a high-frequency humbucker wave, and then passed through a filter capacitor C. O The high-frequency waveform is converted into direct current and transmitted to the load device.

[0093] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A magnetic resonant wireless power transfer system with high-order LC compensation at the receiver, characterized in that, include: Transmitter and receiver; The transmitter includes a transmitter compensation network and a transmitter coil. The transmitter compensation network is connected to the transmitter coil. An AC signal is input to the transmitter compensation network. The transmitter compensation network makes the current in the transmitter coil exhibit constant current characteristics. The transmitter coil transmits electrical energy to the receiver coil through magnetic coupling. The receiving end includes a receiving coil and a receiving end compensation network. The receiving end compensation network includes a high-order LC structure with several orders of LC. The receiving coil is connected to the receiving end compensation network. The receiving coil receives the electrical energy emitted by the transmitting coil and stabilizes the transmission efficiency through the receiving end compensation network. The high-order LC structure in the receiver compensation network includes LC structures of orders two to ten. Each order LC structure includes a capacitor and an inductor. The capacitor has a first connection terminal and a second connection terminal, and the inductor has a first connection terminal and a second connection terminal. The second connection terminal of the capacitor in each order LC structure is connected to the first connection terminal of the inductor. The connection relationship between two adjacent order LC structures is as follows: the second connection terminal of the capacitor in the second order LC is connected to the second connection terminal of the inductor in the previous order LC, and the first connection terminal of the capacitor in the second order LC is connected to the first connection terminal of the capacitor in the previous order LC. The first connection terminal and the second connection terminal of the capacitor in the first order LC structure in the high-order LC structure serve as the input terminal of the high-order LC structure, and the first connection terminal of the capacitor and the second connection terminal of the inductor in the last order LC structure in the high-order LC structure serve as the output terminal of the high-order LC structure. The sum of the reactances of each mesh in the system is zero, and the system operates in a resonant state. According to the KVL equations, the receiver circuit in the resonant state has the following relationship: Among them, U IN I is the input voltage at the transmitter. T Z is the current in the transmitting coil. CP For the capacitor C in the transmitter compensation network P Capacitive reactance, I IN For the input current at the transmitter, I R To receive the coil current, R L For the load of the receiving end, I O I is the output current of the receiving end. n-1 Z represents the current in the (n-1)th order LC structure. M For mutual inductance, C n For a capacitor of the nth order LC structure, L n For an inductor of the nth order LC structure, Z Cn C n Capacitive reactance; Input current I at the transmitter IN The expression is: transmitting coil current I T The expression is: From the current I in the transmitting coil T From the expression, we can see that the transmitting coil current I T Only related to the input voltage and the capacitor C in the transmitter compensation network P It is related to the load, but not to the load; the constant current of the transmitting coil keeps the system's transmission characteristics stable. Receiver coil current I R The expression is: The output current I of the receiver O The expression is: From the output current I O As can be seen from the expression, when the order n of the higher-order LC structure is odd, the topological output current of the circuit topology family is independent of the load and exhibits constant current characteristics; when the order n of the higher-order LC structure is even, the output voltage at the receiving end of the circuit topology family is independent of the load and exhibits constant voltage characteristics. The higher-order LC structure in the receiver compensation network is a second-order LC structure, and the transmitter also includes an inductor L connected in series with the input power supply. P The transmitter and receiver have a total of five meshes. Write the KVL equations for the five voltage meshes: Solving for the efficiency expression of the magnetic resonant wireless power transfer system, where the higher-order LC structure in the receiver compensation network is a second-order LC structure, yields: Among them, Z M For mutual inductance, U IN I is the input voltage at the transmitter. T Z is the current in the transmitting coil. CP For the capacitor C in the transmitter compensation network P The capacitance, Z LP For inductor L P resistance, I IN For the input current at the transmitter, I R To receive the coil current, Z Cn Z is the capacitive reactance of the nth-order LC structure. Ln For L n resistance, R L For the load of the receiving end, I O I is the output current of the receiving end. n-1 R1 represents the current in the (n-1)th order LC structure, and R2, R3, R4, and R5 are all equivalent line resistances.

2. The magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 1, characterized in that, The transmitter compensation network is an LCC series-parallel resonant network, which includes a capacitor C connected in series with the transmitter coil. T The capacitor C connected in parallel with the transmitting coil P and the inductor L connected in series with the transmitting coil P The transmitter also includes an inverter circuit. The input of the inverter circuit is connected to a DC power supply, and the output of the inverter circuit is connected to the transmitter compensation network. The inverter circuit converts the DC input into an AC signal output.

3. The magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 2, characterized in that, The inverter circuit is a full-bridge inverter circuit, which includes MOSFETs Q1, Q2, Q3, and Q4. The drains of MOSFETs Q1 and Q3 are connected, the sources of MOSFETs Q2 and Q4 are connected, the source of MOSFET Q1 is connected to the drain of MOSFET Q2, and the source of MOSFET Q3 is connected to the drain of MOSFET Q4. The drains of MOSFETs Q3 and Q2 serve as the input terminals of the inverter circuit, and the source of MOSFETs Q1 and Q4 serve as the output terminals. MOSFETs Q1, Q2, Q3, and Q4 are all N-type MOSFETs, and their gates are all connected to a PWM signal.

4. The magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 1, characterized in that, The receiving end also includes a rectifier circuit, the input of which is connected to the output of a higher-order LC structure, and the output of which is connected to a load.

5. A magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 4, characterized in that, The rectifier circuit is a full-bridge rectifier circuit, which includes diode D. R1 diode D R2 diode D R3 and diode D R4 Diode D R1 The negative terminal of the diode D is connected. R2 The negative terminal of diode D R3 The positive terminal of the diode D is connected. R4 The positive terminal of diode D R1 The positive terminal of the diode D is connected. R3 The negative terminal of diode D R2 The positive terminal of the diode D is connected. R4 The negative terminal of diode D; R1 The positive electrode and diode D R4 The negative terminal of diode D serves as the input terminal of the rectifier circuit. R3 The positive electrode and diode D R2 The negative terminal is used as the output terminal of the rectifier circuit.

6. A magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 5, characterized in that, The rectifier circuit also includes a rectifier capacitor C. o rectifier capacitor C o The two ends are connected to the two output terminals of the rectifier circuit, respectively.

7. A magnetic resonant wireless power transmission system with high-order LC compensation at the receiving end according to claim 6, characterized in that, The rectifier capacitor C o The capacitor is a polarized capacitor, and the rectifier capacitor C is... o The positive terminal of the diode D is connected. R2 The negative terminal, rectifier capacitor C o The negative terminal of the diode D is connected. R3 The positive pole.

Images